In known air filter arrangements for a combustion engine, particularly an engine of a truck the filter housing often has a releasable bottom which allows a spent filter unit to be taken out and replaced from below, i.e. from the dirty lower side of the arrangement. Although the filter change takes place from the dirty side, there is still risk that in the limited space under the vehicle the new filter unit may scrape against the dirty region in and outside the filter housing, potentially leading to dirt making its way into the filter unit and thereby to the clean side of the air system, and hence to possible damage to the engine. Such a filter change also involves a considerable amount of work and use of space, particularly as the vehicle has to be raised or placed over a greasing pit or the like in a workshop to provide space for the work involved in the change. The operation may comprise removing the bottom of the filter housing, taking out the spent filter unit, cleaning the inside and bottom of the housing, inserting the new filter unit and refitting the bottom.
It would therefore be desirable to be able to change the filter from the upper side of the filter housing.